1. Field of the Invention
This invention generally relates to a measuring device of a swallowing movement which movement occurs at the throat when a person swallows a drink such as beer and a method for measuring the swallowing movement.
2. Description of the Related Art
In conjunction with the movement when a person swallows food, a trial to measure real swallowing movement has been done for the purposes of evaluating a characteristic of food and the swallowing ability of a person.
As the method for evaluating and measuring the swallowing movement, that is, a movement to swallow food, there are diagnostic imaging methods such as a VF method (video X-ray test) and an ultrasonography test. The VF method is such that a subject swallows food including contrast media, and an X-ray motion image from the oral cavity, the pharynx, to the upper esophagus is recorded and it is observed. The ultrasonography test is where a supersonic wave dislocation device is used, and a probe is placed in a cervical part from the lower jaw, and an organ in the oral cavity and an adduction movement of the vocal cords are observed and evaluated in real time. However, in these methods, a direct diagnosis by a picture can be performed, but the swallowing movement cannot be quantified. Therefore, when these are utilized in medical treatments and rehabilitation, it is necessary to evaluate a symptom time-wise and quantitatively to set a treatment policy depending on the symptom to change, but they cannot be utilized to perform such an evaluation. Also, X-rays cannot be used for a physically unimpaired person except a person who is a treatment object, so that a test/a measurement method with the above X-rays can not be utilized for the measurement of the swallowing movement to study such as a feeling at the throat at the time of swallowing a drink and an easiness to swallow food.
In these days, as the method for measuring the swallowing movement that deals with this point, a detecting element with the use of plural pressure sensors is stuck on an anterior region of neck, and a device measuring a larynx vertical motion at the time of swallowing quantitatively has been developed and examined (for example, please see the non-patent document 1).
FIG. 1 is a structural view of a device 1 for measuring the swallowing movement which is developed for measuring the larynx motion, an electromyogram of the suprahyoid muscle group and a swallowing sound at the time of swallowing food.
As shown in FIG. 1, the device 1 comprises a measurement part 10 and an analysis part 20. The measurement part 10 includes a pressure sensor 11, a myogenic potential electrometer electrode 12 and a microphone 13. The pressure sensor 11 is connected to a distorted amplifier 14, the myogenic potential electrometer electrode 12 is connected to an electromyography 15, and the microphone 13 is connected to a charge amplifier 16.
The analysis part 20 comprises an A/D converter 21 which transforms analog signals output by the distorted amplifier 14, the electromyography 15 and the charge amplifier 16 into corresponding digital signals and a personal computer 22 which performs various operations and processes signals from the converter 21.
This system measures at the same time the vertical motion of the thyroid cartilage (that is, the Adam's apple) which is a part of the larynx by the pressure sensor 11, the muscle's activity of the suprahyoid muscles group by the myogenic potential electrometer electrode 12, and a swallowing sound by the microphone 13.
As shown in FIG. 2, the pressure sensor 11 is such that three pairs of sensors become pairs in right and left lengthwise directions (up and down directions), so that six sensors in total are fixed in an urethane foam 11a, which foam is attached to a resin basal part 11b. When the urethane foam 11a is attached to the neck, double-stick tapes are stuck on the urethane foam 11a to be able to fix the urethane foam 11a on the neck. Also, a band 11d is attached on the resin basal part 11b, and sensors are attached in the cervical part by using the band so that sensors are located in the anterior region of neck.
A myogenic potential electrometer electrode (surface electrode) 12 is affixed to an equivalency region of the mylohyoid muscle of the digastric muscle, reference electrodes (standard electrode) are attached to both earlobes. When a thing is swallowed, the device 12 can measure how much force is applied by muscles. A muscle to measure is the suprahyoid muscle group.
The microphone 13 is attached such that the microphone is located beside the cricoid.
FIG. 3 is a view explaining the attachment of the pressure sensor 11 to the anterior region of the neck and the detection principle of the swallowing movement. Also, FIG. 4 is a view showing signal waves obtained from the pressure sensor 11, the myogenic potential electrometer electrode 12, and the microphone 13.
As shown in FIG. 3, the pressure sensor 11 is attached such that among three pairs of sensors, the lowest sensor is located in the normal position which position has no swallowing movement at the thyroid cartilage.
Referring to FIGS. 3 and 4, the swallowing movement when a lump of food is poured into the pharynx from the oral cavity is explained.
First of all, when the lump of food is poured from the oral cavity with the tongue, the suprahyoid muscle group begins an activity as shown in the myogenic potential electrometer output (p1). Following it, the thyroid cartilage which is a part of the larynx begins to rise (FIG. 3 (a)). An output voltage of the pair 2 of the pressure sensor rises (p3); thereby, the pair 3 of the pressure sensor rises (p4) next. At the time of a movement to the lower part of the larynx, it is shown to that vice versa and the thyroid cartilage returns to the original position (p7). As shown in the output wave, after starting the pharynx rising, the swallowing sound obtained from the microphone is begun in a few seconds (p8).
As described the above, the pharynx movement, the electromyogram of the suprahyoid muscle group and the swallowing sound of the swallowing movement when food is swallowed are taken out as electrical signals with the swallowing movement measuring device. For example, the capability to perform an analysis and an evaluation such as a change that occurs due to a kind of food or a difference by a person swallowing is expected.
Non-Patent Document 1: Toyohiko Hayashi et al., “A relationship between a property of rice gruel and a swallowing change—Evaluation by a simultaneous measurement of pharynx movement/EMG/swallowing sound”, Japan A feeding/Swallowing Rehabilitation Study Group Magazine 6 (2):0-0, 2002.